Power tools used in the construction and repair of buildings and other structures are often connected by long electrical cords to an available wall receptacle and, therefore, are subject to power interruptions that are caused by accidental withdrawal of a plug from a remote wall receptacle that may be hidden from view. When this occurs the cable must be traced back to the wall receptacle, which may not be in immediate view from the work site. A delay is thus imposed causing down time and a stoppage in the progress of the job at hand until the power connection is restored. According, it is desirable to lock the plug to the wall receptacle but to do so automatically at the time that the plug is initially inserted, and in a manner such that the plug may be immediately withdrawn from the wall receptacle by one hand for insertion at a different location as the project at hand may demand.